1. Field of the Invention
The present invention relates to a portable information processor, and more particularly relates to a portable information processor comprising a main section equipped with a CPU, a main memory, input unit, display unit, and so forth, and an extension section equipped with an extension power supply, external storage unit, various interfaces, and so forth, both detachably configured.
2. Background Information
The need for faster processing has driven up the operating frequency of the CPUs used in personal computers in recent years, and this has been accompanied by a rise in power consumption. Particularly with portable information processors such as laptop computers and PDAs, mounting density is increased in order to make the products more compact, so an increase in power consumption leads to more heat being generated.
Information processors such as these normally make use of a cooling fan or some other kind of cooling unit such as a heat sink or heat pipe, and there have been efforts to learn how efficient these are at cooling. In order to handle the full operation of the CPU, the cooling unit can be made larger, or two or more cooling unit can be employed, or the speed of the cooling fan can be raised.
Increasing the size of the cooling unit or the number of units used is contrary to the goal of making the apparatus more compact, and makes it difficult to find enough space to install the unit or units in the apparatus. If a cooling fan is operated at high speed it generates noise, requiring the installation of a silencing unit for damping this noise. This silencing unit can consist of a sound absorbent material or a silencer installed inside the apparatus, but here again this makes it difficult to find enough space to install the equipment while still maintaining a compact apparatus size, so no effective way to make the apparatus quieter has been found.
There are portable information processors comprising an extension section (called a docking station, etc.) equipped with an extension power supply, external storage unit, various interfaces, and so forth, and a main section equipped with a CPU, a main memory, input unit, display unit, and so forth, with the extension section and main section being detachable from each other. With a configuration such as this, including an extension section, it has been proposed that the cooling unit be installed on the extension section side so as to remove the heat generated on the main section side (see, for example, Japanese Patent No. 2,908,418).
In Japanese Patent No. 2,908,418, a heat sink is provided on the main section side, while a cooling unit such as a cooling fan is provided on the extension section side, and when the main section is used coupled with the extension section, the heat sink on the main section side and the cooling unit on the extension section side are connected by a thermal conductor such as silicone rubber, so that heat on the main section side is radiated on the extension section side.
It has been proposed that noise can be suppressed by controlling the speed of the cooling fan provided on the main section side according to the power supply management mode, etc. (see, for example, JP H10-11 176A).